Thermoplastic elastomeric resin composition and a process for the preparation thereof

ABSTRACT

The invention provides a process for the preparation of a thermoplastic elastomeric resin composition comprising melt kneading  
     (a) 100 parts by weight of a block copolymer consisting of at least two polymeric blocks (A) composed mainly of a vinyl aromatic compound and at least one polymeric block (B) composed mainly of a conjugated diene compound, and/or a hydrogenated block copolymer obtained by hydrogenating said block copolymer,  
     (b) 40 to 240 parts by weight of a non-aromatic softening agent for rubber,  
     (c) 5 to 300 parts by weight of polyethylene or a copolymer composed mainly of ethylene, and  
     (d) 5 to 60 parts by weight of polypropylene or a copolymer composed mainly of propylene,  
     characterized in that the process comprises the following steps:  
     (I) melt kneading the whole amounts of components (a), (b) and (d) and a part of component (c), and, at the same time or subsequently, melt kneading these with (f) an organic peroxide, and  
     (II) melt kneading the product obtained from step (I) with the remaining part of component (c),  
     and component (c) is one which has been prepared using a single site catalyst. The obtained composition is soft and excellent in heat deformation resistance and mechanical strength, moldability and processability. The present invention also provide a thermoplastic elastomeric resin composition comprising the above components (a), (c) and (d) in an amount of 100 parts by weight, 5 to 150 parts by weight and 5 to 80 parts by weight, respectively. The composition is soft and excellent in heat deformation resistance and mechanical strength, moldability and processability and shows good results in the extraction tests.

FIELD OF THE INVENTION

[0001] The present invention relates to a process for the preparation ofa thermoplastic elastomeric resin composition.

[0002] The present invention also relates to a thermoplastic elastomericresin composition.

PRIOR ART

[0003] Thermoplastic elastomeric resins which are rubber-like materials,do not need a vulcanization process and have thermoplastic resin-likemolding processability are attracting attention in the fields of autoparts, parts for electric appliances, electric wire insulation,footwears and general goods, and in the field of cap sealing materials.

[0004] Various types of such thermoplastic elastomeric resins have beendeveloped and put on sale, such as polyolefine type, polyurethane type,polyester type, polystyrene type and polyvinyl chloride type.

[0005] Among those, polystyrene type thermoplastic elastomeric resinssuch as styrene-butadiene block copolymers (SBS) and styrene-isopreneblock copolymers (SIS) and hydrogenated resins thereof have highsoftness and good rubber elasticity at normal temperature. Further,thermoplastic elastomeric resin compositions obtained from these showgood processability.

[0006] However, these block copolymer compositions are unsatisfactory incompression set at a high temperature, particularly at 100° C. and,moreover, tensile properties deteriorate considerably at 80° C. or more.Thus, such compositions do not meet the levels of properties required inthe fields of vulcanized rubber.

[0007] Meanwhile, the thermoplastic elastomers mentioned above are alsoattracting attention in the fields of cap sealing materials.Particularly, polyolefin type thermoplastic elastomers are used widelybecause of their high sanitary reliability and cheapness. However, thesepolyolefin type thermoplastic elastomers are poor in softness and,therefore, exhibit poor sealing property.

[0008] Alternatively, polystyrene type thermoplastic elastomeric resinssuch as SBS and SIS and hydrogenated resins thereof have high softnessand good rubber elasticity at normal temperature. Further, thermoplasticelastomeric resin compositions obtained from these show goodprocessability. Accordingly, these are used widely as an alternate ofvulcanized rubber. However, these polystyrene type thermoplasticelastomer compositions cannot meet the n-heptane extraction test of thetests of Notification No. 20 of the Japanese Welfare Ministry, becausesoftening agents such as paraffinic oil are generally added to thesecompositions in order to control their hardness. Accordingly, it is hardto use them as a cap sealing. Alternatively, if the paraffinic oil isnot used, the softness and moldability of them deteriorate.

[0009] In order to solve such a drawback, there has been proposed acomposition containing polybutene or polyisobutene as a softening agent.However, the composition disclosed are poor in heat resistance at 120°C.

[0010] Another resin compositions which comprise the block copolymerused as component (a) in the present invention has been proposed inJapanese Patent Application Laid-Open Nos. Sho-53-138451/1978,53-138453/1978, 53-138454/1978, 53-138456/1978, 53-138458/1978,53-138460/1978 and 53-138461/1978. However, heat resistance is poor.

[0011] The composition disclosed in Japanese Patent ApplicationLaid-Open No. 58-215446/1983 comprises isotactic polypropylene. Thiscomposition is excellent in mechanical strength and heat resistance.However, the hardness is in the D hardness area. Thus, it cannot be saidthat the composition is excellent in sealing property.

SUMMARY OF THE INVENTION

[0012] A purpose of the invention is to provide a process for thepreparation of a thermoplastic elastomer composition which is soft andexcellent in heat deformation resistance, mechanical strength,moldability and processability.

[0013] The present inventors have noticed that an organic peroxidegenerate radicals, which then effect crosslinking of polyethylene andmolecule cutting of polypropylene, particularly effect molecule cuttingof polypropylene to deteriorate the physical properties in the elastomercomposition obtained. We have now found that when a smallest amount ofpolypropylene needed for increasing the flowability during melting isadded and an amount of polyethylene for obtaining proper dispersion isused, it is possible to enhance the crosslinking of polyethylene anddispersion of rubber component and to prepare the thermoplasticelastomer composition having excellent properties. This finding leads tothe present invention.

[0014] Thus, the present invention provides a process for thepreparation of a thermoplastic elastomeric resin composition comprisingmelt kneading

[0015] (a) 100 parts by weight of a block copolymer consisting of atleast two polymeric blocks (A) composed mainly of a vinyl aromaticcompound and at least one polymeric block (B) composed mainly of aconjugated diene compound, and/or a hydrogenated block copolymerobtained by hydrogenating said block copolymer,

[0016] (b) 40 to 240 parts by weight of a non-aromatic softening agentfor rubber,

[0017] (c) 5 to 300 parts by weight of polyethylene or a copolymercomposed mainly of ethylene, and

[0018] (d) 5 to 60 parts by weight of polypropylene or a copolymercomposed mainly of propylene,

[0019] characterized in that the process comprises the following steps:

[0020] (I) melt kneading the whole amounts of components (a), (b) and(d) and a part of component (c), and, at the same time or subsequently,melt kneading these with (f) an organic peroxide, and

[0021] (II) melt kneading the product obtained from step (I) with theremaining part of component (c),

[0022] and component (c) is one which has been prepared using a singlesite catalyst.

[0023] In a preferred embodiment, a weight ratio of the amount ofcomponent (c) used in step (I) and that in step (II) is 90:10 to 10:90.

[0024] In another preferred embodiment, component (f) is used in anamount of 0.1 to 1.5 parts by weight per 100 parts by weight of a totalamount of components (a), (b), (c) and (d).

[0025] In another preferred embodiment, 0.1 to 3.5 parts by weight of acrosslinking aid per 100 parts by weight of a total amount of components(a), (b), (c) and (d) are used together with component (f) in step (I).

[0026] In another preferred embodiment, the whole amount of

[0027] (e) at most 100 parts by weight of an inorganic filler is meltmeaded in the initial stage of step (I).

[0028] In another preferred embodiment, (h) at most 3.0 parts by weightof an antioxidant per 100 parts by weight of a total amount ofcomponents (a), (b), (c) and (d) are used in step (I).

[0029] In another preferred embodiment, an additional amount ofcomponent (d) is added in step (II) and melt kneaded.

[0030] Another purpose of the invention is to provide a thermoplasticelastomer composition which is soft and excellent in heat deformationresistance, mechanical strength, moldability and processability and usedproperly as a sealing material.

[0031] Thus the present invention provides a thermoplastic elastomericresin composition comprising

[0032] (a) 100 parts by weight of a block copolymer consisting of atleast two polymeric blocks (A) composed mainly of a vinyl aromaticcompound and at least one polymeric block (B) composed mainly of aconjugated diene compound, and/or a hydrogenated block copolymerobtained by hydrogenating said block copolymer,

[0033] (c) 5 to 150 parts by weight of polyethylene or a copolymercomposed mainly of ethylene, and

[0034] (d) 5 to 80 parts by weight of polypropylene or a copolymercomposed mainly of propylene,

[0035] characterized in that component (c) is one which has beenprepared using a single site catalyst.

[0036] In a preferred embodiment, the composition further comprises

[0037] (b) 40 to 240 parts by weight of a non-aromatic softening agentfor rubber.

[0038] In another preferred embodiment, the composition furthercomprises

[0039] (e) 0.01 to 100 parts by weight of an inorganic filler

PREFERRED EMBODIMENTS OF THE INVENTION

[0040] Component (a), Block Copolymer

[0041] Component (a) used in the invention is a block copolymerconsisting of at least two polymeric blocks (A) composed mainly of aviny aromatic compound and at least one polymeric block (B) composedmainly of a conjugated diene

[0042] compound, or a hydrogenated block copolymer obtained byhydrogenating said block copolymer, or a mixture thereof, such as vinylaromatic compound-conjugated diene compound block copolymers having astructure, A-B-A, B-A-B-A or A-B-A-B-A, or those obtained byhydrogenating such. The block copolymer and/or the hydrogenated blockcopolymer (hereinafter referred to as (hydrogenated) block copolymer)contains 5 to 60% by weight, preferably 20 to 50% by weight, of a vinylaromatic compound. Preferably, the polymeric block A composed mainly ofa vinyl aromatic compound consists wholly of a vinyl aromatic compoundor is a copolymeric block comprising more than 50% by weight, preferablyat least 70% by weight, of a vinyl aromatic compound and an optionalcomponent such as a conjugated diene compound and/or a hydrogenatedconjugated diene compound (hereinafter referred to as (hydrogenated)conjugated diene compound). Preferably, the polymeric block B composedmainly of a (hydrogenated) conjugated diene compound is composed solelyof a (hydrogenated) conjugated diene compound or is a copolymeric blockcomprising more than 50% by weight, preferably at least 70% by weight,of a (hydrogenated) conjugated diene compound with an optional componentsuch as a vinyl aromatic compound. The vinyl compound or the(hydrogenated) conjugated diene compound may be distributed at random,in a tapered manner (i.e., a monomer content increases or decreasesalong a molecular chain), in a form of partial block or mixture thereofin the polymeric block A composed mainly of a vinyl aromatic compound orthe polymeric block B composed mainly of a (hydrogenated) conjugateddiene compound, respectively. When two or more of the polymeric block Acomposed mainly of a vinyl aromatic compound or two or more of thepolymeric block B composed mainly of a (hydrogenated) conjugated dienecompound are present, they may be same with or different from each otherin structure.

[0043] The vinyl aromatic compound to compose the (hydrogenated) blockcopolymer may be one or more selected from, for instance, styrene,α-methyl styrene, vinyl toluene and p-tert.-butyl styrene, preferablystyrene. The conjugated diene compound may be one or more selected from,for instance, butadiene, isoprene, 1,3-pentadiene, and2,3-dimethyl-1,3-butadiene, preferably butadiene and/or isoprene.

[0044] Any micro structure may be selected in the polymeric block Bcomposed mainly of the conjugated diene compound. It is preferred thatthe butadiene block has 20 to 50%, more preferably 25 to 45%, of1,2-micro structure. In the polyisoprene block, it is preferred that 70to 100% by weight of isoprene is in 1,4-micro structure and at lest 90%of the aliphatic double bonds derived from isoprene is hydrogenated.

[0045] A weight average molecular weight of the (hydrogenated) blockcopolymer with the aforesaid structure to be used in the invention ispreferably 5,000 to 1,500,000, more preferably 10,000 to 550,000,further more preferably 100,000 to 550,000, particularly 100,000 to400,000. A number average molecular weight is preferably 5,000 to1,500,000, more preferably 10,000 to 550,000, particularly 100,000 to400,000. A ratio of the weight average molecular weight (Mw) to thenumber average molecular weight (Mn), Mw/Mn, is preferably 10 or less,more preferably 5 or less, particularly 2 or less.

[0046] Molecule structure of the (hydrogenated) block copolymer may belinear, branched, radial or any combination thereof.

[0047] Many methods were proposed for the preparation of such blockcopolymers. As described, for instance, in JP Publication 40-23798/1965,block polymerization may be carried out using a lithium catalyst or aZiegler catalyst in an inert solvent. The hydrogenated block copolymermay be obtained by hydrogenating the block copolymer thus obtained inthe presence of a hydrogenation catalyst in an inert solvent.

[0048] Examples of the (hydrogenated) block copolymer include SBS, SIS,SEBS and SEPS. A particularly preferred (hydrogenated) block copolymerin the invention is a hydrogenated block copolymer with a weight averagemolecular weight of 50,000 to 550,000 which is composed of polymericblock A composed mainly of styrene and polymeric block B which iscomposed mainly of isoprene and in which 70 to 100% by weight ofisoprene has 1,4-micro structure and 90% of the aliphatic double bondsderived from isoprene is hydrogenated More preferably, 90 to 100% byweight of isoprene has 1,4-micro structure in the aforesaid hydrogenatedblock copolymer.

[0049] Component (b), Non-Aromatic Softening Agent for Rubber

[0050] Non-aromatic mineral oils and non-aromatic liquid or lowmolecular weight synthetic softening agents may be used as component (b)of the invention. Mineral oil softening agents used for rubber aremixtures of aromatic cyclic ones, napththenic cyclic ones and paraffinicones. Those in which 50% or more of the whole carbon atoms is inparaffinic chains are called a paraffinic type; those in which 30 to 40%of the whole carbon atoms is in naphthenic rings are called a naphthenictype; and those in which 30% or more of the whole carbon atoms is inaromatic rings are called an aromatic type. Mineral oil softening agentsfor rubber to be used as component (b) according to the invention arepreferably of the aforesaid paraffinic or naphthenic type. Aromaticsoftening agents are improper, because the dispersion in component (a)is poor. Paraffinic ones are preferred as component (b). Among theparaffinic ones, those with a less content of aromatic cyclic componentsare particularly preferred.

[0051] The non-aromatic softening agents for rubber have a kineticviscosity at 37.8° C. of 20 to 500 cSt, a pour point of −10 to −15° C.and a flash point (COC) of 170 to 300° C.

[0052] Component (b) is blended in an amount of at most 240 parts byweight, preferably at most 180 parts by weight, and at least 40 parts byweight, preferably 80 parts by weight, per 100 parts by weight ofcomponent (a). If the amount exceeds the upper limit, bleedout ofsoftening agent occurs easily and stickiness may be given to the finalproducts in some cases and the mechanical properties deteriorate. If theamount is below the lower limit, there is no problem in practice, but aload to the extruder increases during the process and molecule cuttingoccurs due to exothermic shearing. The softness of the compositionobtained deteriorates, too.

[0053] Component (c), Polyethylene or a Copolymer Composed Mainly ofEthylene

[0054] Which Is Prepared Using a Single Site Catalyst

[0055] As the polyethylene or a copolymer composed mainly of ethylenewhich is prepared using a single site catalyst, use may be made of oneor more substances selected from polyethylene, for instance, highdensity polyethylene (polyethylene prepared in a low pressure method),low density polyethylene (polyethylene prepared in a high pressuremethod), linear low density polyethylene (copolymers of ethylene with asmaller amount, preferably 1 to 10 molar % of α-olefin such as butene-1,hexene-1 or octene-1); and olefinic copolymers such asethylene-propylene copolymer, ethylene-vinyl acetate copolymer andethylene-acrylate copolymer. Particularly preferable substances areethylene-octene copolymer having a polymer density of at most 0.90 g/cm³or ethylene-hexene copolymer having a polymer density of at least 0.90g/cm³ which are prepared using a metallocene catalyst (single sitecatalyst). When Tm of these copolymer is not higher than 100° C., it isnecessary to add and crosslink them by the time of crosslinking at thelatest. Tm disappears by the crosslinking and, therefore, fusion ofoctene or hexene does not occur. If the addition of them is carried outafter the crosslinking, fusion at 30 to 60° C. of octene or hexeneremains and, therefore, the heat resistance is decreased.

[0056] The (co)polymer used as component (c) includes olefinic polymerswhich are prepared using a catalyst for olefine polymerization which isprepared in accordance with the method described in Japanese PatentApplication Laid-Open Sho-61-296008/1986 and which is composed of acarrier and a reaction product of metallocene having at least one metalselected from the 4b group, 5b group and 6b group in the periodic tablewith alumoxane, the reaction product being formed in the presence of thecarrier.

[0057] Another example of component (c) is an olefinic polymer preparedusing a metal coordinated complex described in Japanese PatentApplication Laid-Open Hei-3-163008, which metal coordinated complexcontains a metal selected from the group 3 (except scandium), groups 4to 10 and the lanthanoid group and a delocalized π-bonding partsubstituted by a constrained inducing part, and is characterized in thatsaid complex has a constrained geometrical form around said metal atom,and a metal angle between a center of the delocalized substitutedπ-bonding part and a center of at least one remaining substituted partis less than that in a comparative complex which is different from itonly in that a constrained inducing substituted part is substituted witha hydrogen, and wherein in each complex having further at least onedelocalized substituted π-bonding part, only one, per metal atom, of thedelocalized substituted π-bonding parts is cyclic.

[0058] The (co)polymer used as component (c) has an MFR determined at190° C. and a load of 2.16 kg of preferably 0.1 to 10.0 g/10 min., morepreferably 0.3 to 5.0 g/l 0 min. In the present composition, MFR of 0.3to 2.0 g/10 min. is particularly preferred.

[0059] In the present process, component (c) is blended in an amount ofat most 300 parts by weight, preferably at most 250 parts by weight, andpreferably at least 5 parts by weight, per 100 parts by weight ofcomponent (a). If the amount is below the lower limit, the presenteffects cannot be obtained. If the amount exceeds the upper limit,softness of the elastomer composition obtained is lost and bleedout ofsoftening agent (b) occurs easily.

[0060] In the present composition, component (c) is contained in anamount of at most 150 parts by weight, preferably at most 130 parts byweight, and preferably at least 5 parts by weight, more preferably atleast 70 parts by weight, per 100 parts by weight of component (a). Ifthe amount is below the lower limit, softness is lost. If the amountexceeds the upper limit, the heat resistance of the elastomercomposition deteriorates.

[0061] Component (d), Polypropylene or a Copolymer Composed Mainly ofPropylene

[0062] The polypropylene or a copolymer composed mainly of propyleneattains an effect of improving dispersion of the rubber in thecomposition obtained so as to improve appearance of a molded article.Further, the heat resistance may be also improved. The component is anolefinic (co)polymer which is pyrolyzed by the heat treatment in thepresence of peroxide to decrease its molecular weight and, therefore,its melting flowability increases. Examples of such include isotacticpolypropylenes, and copolymers of propylene with other α-olefine such asethylene, 1-butene, 1-hexene or 4-methyl-1-pentene.

[0063] Preferably, component (d) has Tm of 150 to 167° C. and ΔHm of 25to 83 mJ/mg, as determined by DSC (differential scanning calorimetry) onits homopolymeric part. Crystallinity may be estimated from Tm and ΔHm.If Tm and ΔHm are out of the aforesaid ranges, rubber elasticity at 100°C. or higher of the elastomer composition obtained is not improved.

[0064] In the present process, component (d) has an MFR (ASTM D-1238,Condition L, 230° C.) of preferably 0.1 to 50 g/10 min., more preferably0.5 to 20 g/10 min. If the MFR is less than 0.1 g/10 min., moldabilityof the elastomer composition obtained deteriorates. If it exceeds 50g/10 min., rubber elasticity of the elastomer composition obtaineddeteriorates.

[0065] In the present process, component (d) is blended in an amount ofat most 60 parts by weight, preferably at most 30 parts by weight, andat least 5 parts by weight, preferably at least 10 parts by weight, per100 parts by weight of component (a). If the amount is less than thelower limit, moldability of the elastomer composition obtaineddeteriorates. If it exceeds the upper limit, the elastomer compositionobtained is too hard and lacks softness, so that an article withrubber-like touch cannot be obtained and, further, bleedout is observed.

[0066] The component (d) may be added and melt kneaded after the meltkneading in the presence of an organic peroxide to control the hardnessof the composition or to control moldability such as appearance orshrinkage. In this case, component (d) has an MFR (ASTM D-1238,Condition L, 230° C.) of preferably 0.1 to 200 g/10 min., morepreferably 0.5 to 60 g/10 min. If the MFR is not within the above range,the aforesaid drawbacks occur. The amount in this case is at most 50parts by weight, preferably at most 20 parts by weight, and at least 5parts by weight, preferably at least 10 parts by weight, per 100 partsby weight of component (a). If the amount is less than the lower limit,adjustment of moldability of the elastomer composition obtained isinsufficient. If it exceeds the upper limit, the elastomer compositionobtained is too hard and lacks softness, so that an article withrubber-like touch cannot be obtained.

[0067] In the present elastomer composition, component (d) is containedin an amount of 5 to 80 parts by weight, preferably 30 to 50 parts byweight, per 100 parts by weight of component (a). If the amount is belowthe lower limit, the moldability of the elastomer composition was poor.If the amount exceeds the upper limit, the softness and rubberelasticity of the elastomer composition deteriorate.

[0068] Component (e), Inorganic Filler

[0069] Inorganic fillers may be blended, if needed. The fillers improvesome physical properties, such as compression set of a molded article,and further offer an economical advantage as an extender. Anyconventional inorganic fillers may be used, such as calcium carbonate,talc, magnesium hydroxide, mica, clay, barium sulfate, natural silica,synthetic silica (white carbon), titanium oxide, and carbon black. Amongthose, calcium carbonate and talc are particularly preferred, which meetthe test of Notification No. 20 of the Japanese Welfare Ministry.

[0070] The inorganic filler may be blended in an mount of at most 100parts by weight per 100 parts by weight of component (a). If the amountexceeds 100 parts by weight, mechanical strength of the elastomercomposition obtained is very low and, further, its hardness is so highthat its flexibility is lost and an article with rubber-like touchcannot be obtained. In addition, the moldability deteriorates.

[0071] Component (f), Organic Peroxide

[0072] An organic peroxide enhances the crosslinking of component (c)and molecule cutting of component (d) to increase flowability of thecomposition during melt kneading and, therefore, makes dispersion of arubber component good. Examples of the organic peroxides used in theinvention include dicumyl peroxide, di-tert.-butyl peroxide,2,5-dimethyl-2,5-di(tert.-butylperoxy) hexane,2,5-dimethyl-2,5-di(tert.-butylperoxy) hexine-3,1,3-bis(tert.-butylperoxyisopropyl) benzene,1,1-bis(tert.-butylperoxy)-3,3,5-trimethylcyclohexane,n-butyl-4,4,-bis(tert.-butylperoxy)valerate, benzoylperoxide,p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide,tert.-butylperoxy benzoate, tert.-butylperoxyisopropyl carbonate,diacetyl peroxide, lauroyl peroxide, and tert.-butylcumyl peroxide.Among those, most preferred are2,5-dimethyl-2,5-di(tert.-butylperoxy)hexane and2,5-dimethyl-2,5-di(tert.-butylperoxy) hexine-3 in terms of smell,coloring and scorch stability.

[0073] The amount of component (f) added is determined withconsideration of the-amounts of the aforesaid components (a) to (e) and,particularly, the quality of the thermoplastic elastomer obtained. It isblended preferably in an amount of at most 1.5 parts by weight,particularly at most 1.0 parts by weight, and preferably at least 0.1part by weight, per 100 parts by weight of a total amount of components(a) to (d). If the amount is more than the upper limit, the moldabilitybecomes worse, while it is less than the lower limit, it tends not toattain sufficient crosslinking and, therefore, the heat resistance andmechanical strength of the elastomer obtained becomes worse.

[0074] Component (g), Crosslinking Aid

[0075] In the crosslinking treatment in the presence of the organicperoxide in the process for the preparation of a thermoplastic elastomercomposition according to the invention, a crosslinking aid may beblended and thereby uniform and effective crosslinking reaction may becarried out. Examples of the crosslinking aid include polyvalent vinylmonomers such as divinylbenzene, triallylcyanurate, vinyl butylate andvinyl stearate and polyvalent methacrylate monomers such asethyleneglycol dimethacrylate, diethyleneglycol dimethacrylate,triethyleneglycol dimethacrylate, polyethyleneglycol dimethacrylate,trimethylolpropane trimethacrylate and allyl methacrylate, and diallyesters of orthophthalic acid, isophthalic acid or terephthalic acid.Among these, triethylenegloycol dimethacrylateis particularly preferred,because this is easy to handle and attains a well compatibility withcomponent (c), a main component in the composition, and this has asolubilizing action for the peroxide to act as a dispersion aid for theperoxide, so that the crosslinking action in the heat treatment isuniform and efficient to give a cross-linked thermoplastic elastomerwith a good balance between hardness and rubber elasticity.

[0076] The amount of the crosslinking aid blended is also determinedwith consideration of the amounts of the aforesaid components (a) to (e)and, particularly, the quality of the thermoplastic elastomer obtained.It is blended preferably in an amount of at most 3.5 parts by weight,particularly at most 2.5 parts by weight, and preferably at least 0.1part by weight, per total 100 parts by weight of components (a) to (d).If the amount is more than the upper limit, a degree of crosslinkingtends to decrease because of self polymerization, while it is less thanthe lower limit, it tends not to attain the effect of this materialsufficiently.

[0077] Component (h), Antioxidant

[0078] Antioxidant may also be added, if needed, such as phenolicantioxidant such as 2,6-di-tert.-butyl-p-cresol,2,6-di-tert.-butylphenol, 2,4-di-methyl-6-tert.-butylphenol,4,4-dihydroxydiphenyl, andtris(2-methyl-4-hydroxy-5-tert.-butylphenyl)butane, phosphite typeantioxidants and thioether type antioxidants. Among those, the phenolicantioxidants and the phosphite type antioxidants are preferred.

[0079] The amount of the antioxidant is preferably 3 parts by weight orless, more preferably 1 part by weight or less, per total 100 parts byweight of components (a) to (d).

[0080] In the present invention, it is possible to blend variousconventional additives such as anti-blocking agents, sealingproperty-improving agents, heat stabilizers, light stabilizers, UVabsorbers, lubricants, nucleating agents and colorants in addition tothe aforesaid components, depending on the applications.

[0081] The present process will be further explained hereinafter.

[0082] The present process comprises the following steps:

[0083] (I) melt kneading the whole amounts of components (a), (b) and(d) and optionally component (e) and a part of component (c), and, atthe same time or subsequently, melt kneading these with (f) an organicperoxide, and

[0084] (II) melt kneading the product obtained from step (I) with theremaining part of component (c).

[0085] In the present process, component (c) is portionwise added andmelt kneaded in steps (I) and (II). A weight ratio of the amount ofcomponent (c) used in step (I) and that in step (II) is preferably 90:10to 10:90, more preferably 50:50 to 20:80. If the amount melt kneaded instep (I) is too much, a load to the extruder increases during theprocess because of an excess proceeding of crosslinking and moleculecutting occurs due to exothermic shearing. Moreover, dispersion ofcomponent (c) deteriorates so that this affects adversely the propertiesof the elastomer composition obtained. If the amount melt kneaded instep (I) is too little, proper crosslinking cannot be obtained.

[0086] When component (g), crosslinking aid, mentioned above is used, itis preferably melt kneaded together with component (f), organic peroxidein step (I), whereby the aforesaid effects may be attained.

[0087] Next, one embodiment of the present process will be described.For example, the whole amounts of components (a), (b) and (d) andcomponent (e), if used, and a part of component (c) are melt kneaded,together with optional additives such as an antioxidant, a lightstabilizer, a pigment, a flame retardant and a lublicant. The means formelt kneading are not restricted to particular ones and any conventionalmeans may be used, such as single screw extruders, twin screwsextruders, rolls, Banbury mixers, and various kneaders. A melt kneadingtemperature is preferably 160 to 180° C. Next, component (f) andpreferably component (g) are added to the product obtained by this meltkneading and melt kneaded together, whereby partial crosslinking ofcomponent (c) may be attained. The melt kneading may be carried outgenerally on, for example, twin screws extruders or Banbury mixers.Subsequently, the remaining part of component (c) and, if desired,component (d) is further added to the product obtained by this meltkneading and melt kneaded. A melt kneading temperature for crosslinkingis preferably 180 to 240° C., more preferably 180 to 220° C. This meltkneading may be carried out using, for example, single screw extruders,twin screws extruders, rolls, Banbury mixers, and various kneaders. Forexample, when a twin screws extruder with an L/D ratio of 47 or more ora Banbury mixer is used, it is possible to carry out the aforesaidprocess continuously.

[0088] The thermoplastic elastomeric resin composition of the presentinvention will be further explained hereinafter.

[0089] The present elastomer composition comprises 100 parts by weightof composnent (a), 5 to 150 parts by weight of component (c) and 5 to 80parts by weight of component (d). These components are describedspecifically hereinbefore.

[0090] The present composition may contain any other componentsmentioned above, if needed.

[0091] The present composition may be prepared by melt kneading theaforesaid components (a), (c) and (d) in any order or at the same time.

EXAMPLES

[0092] The present invention is further elucidated with reference to thefollowing Examples and Comparison Examples, which is not intended tolimit the invention. The evaluation methods used were as follows:

[0093] 1) Hardness: determined in accordance with the JapaneseIndustrial Standards (JIS) K 7215. Pressed sheets having a thickness of6.3 mm were used as test pieces.

[0094] 2) Tensile strength: determined in accordance with JIS K 6301using a test piece which was obtained by punching out a pressed sheethaving a thickness of 1 mm by a No. 3 dumbbell die. The tensile speedwas 500 mm/min. In Examples 1 to 5 and Comparison Examples 1 to 10, thetest temperature was room temperature (23° C.), 60° C. or 80° C.

[0095] 3) Tensile elongation: determined in accordance with JIS K 6301using a test piece which was obtained by punching out a pressed sheethaving a thickness of 1 mm by a No. 3 dumbbell die. The tensile speedwas 500 mm/min.

[0096] 4) Stress at 100% elongation: determined in accordance with JIS K6301 using a test piece which was obtained by punching out a pressedsheet having a thickness of 1 mm by a No. 3 dumbbell die. The tensilespeed was 500 mm/min.

[0097] 5) Impact resilience: determined in accordance with BS903 using apressed sheet having a thickness of 4 mm as a test piece.

[0098] 6) Compression set: determined in accordance with JIS K 6262using a pressed sheet having a thickness of 6.3 mm as a test piece.Conditions: 25% deformation at 100° C.×70 hrs in Examples 1 to 5 andComparison Examples 1 to 10, or at 125° C.×1 hr in Examples 6 to 11 andComparison Examples 11 to 17.

[0099] 7) Tearing strength: determined in accordance with JIS K 6301using a test piece which was obtained by punching out a pressed sheethaving a thickness of 2.5 mm by a B type dumbbell die. The tensile speedwas 500 mm/min.

[0100] 8) Oil resistance: determined in accordance with JIS K 6301 usinga test piece which was obtained by punching out a pressed sheet having athickness of 1 mm by a No. 3 dumbbell die. ASTM No. 2 oil was used.Tensile strength retained and elongation retained were measured afterdipping at 100° C.×24 hrs. The tensile speed was 500 mm/min.

[0101] 9) Moldability: determined by molding a composition into a sheetof 12.5×13.5×1 mm on a 120 tons injection molding machine in thefollowing conditions. molding temperature 220° C., mold temperature 40°C., injection rate 55 mm/sec., injection pressure 1400 kg /cm², holdingpressure 400 kg /cm², injection time 6 seconds, cooling time 45 seconds.

[0102] It was observed whether delamination, deformation or flow markswhich extremely deteriorated appearance was present or not. ⊚ very good◯ good X bad

[0103] 10) Extraction tests: carried out according to the test ofNotification No. 20 of the Japanese Welfare Ministry, using a pressedsheet having a thickness of 1.0 mm as a test piece.

[0104] Test items:

[0105] Oily foods elution test (eluting solution:n-heptane),

[0106] Aqueous foods elution test (eluting solution:water),

[0107] Alcohol elution test (eluting solution: 20% ethanol), and

[0108] Determination of the amount of potassium permanganate consumed bythe eluted product.

[0109] 11) Bleed-out property: the molded sheet obtained from (9) wascompressed by 50% under the conditions of 100° C.×22 hrs. It wasobserved whether bleeding or blooming of low molecular weight substanceswas visually observed or not, and whether stickiness was felt or not intough by fingers. ◯ good X bad

[0110] 12) DSC, determined as follows:

[0111] The aforesaid molded article was cut to obtain an about 20 mgpiece. This was used as a sample for the determination of DSC. DSC wasdetermined using a DSC220C, SII, ex Seiko Electronic Industries Ltd., ina range of −50° C. to 200° C. at a rate of 10° C./min. to obtain glasstransition temperature, Tg₁, melting point, Tm₁ and Tm₂, andcrystallization temperature, Tc₁ and Tc₂, wherein Tm₁ and Tc₁ areattributed to polyethylene and Tm₂ and Tc₂ to polypropylene.

[0112] 13) Gloss: determined in accordance with JIS Z 8741 on theaforesaid molded article. The larger the values are, the more smooth thesurface is, and the smaller the values are, the more rough the surfaceis.

[0113] Materials used:

[0114] Component (a): hydrogenated block copolymer, Septon 4077, ex.Kuraray Inc.,

[0115] styrene content: 30% by weight,

[0116] isoprene content: 70% by weight,

[0117] number average molecular weight: 260,000,

[0118] weight average molecular weight: 320,000,

[0119] molecular weight distribution: 1.23, and

[0120] hydrogenation ratio: at least 90%.

[0121] Component (b): softening agent for rubber, Diana Process Oil,PW-90, ex Idemitsu Kosan Co.,

[0122] weight average molecular weight: 539,

[0123] paraffinic carbon content: 71%, and

[0124] naphthenic carbon content: 29%.

[0125] Component (c):

[0126] (c-1) ethylene-octene copolymer, Engage EG8150, trade mark, exDow Chemical Japan Inc.,

[0127] density: 0.868 g/cm³,

[0128] melt index, determined at 190° C. and a load of 2.16 kg: 0.5 g/10min.

[0129] (c-2) ethylene-hexene copolymer, SP2520, trade mark, ex MitsuiPetrochemical Industries Inc.,

[0130] density: 0.928 g/cm³,

[0131] melt index, determined at 190° C. and a load of 2.16 kg 1.7 g/10min.

[0132] (c-3) polyethylene for comparison, which had not been preparedwith a single site catalyst,

[0133] V-0398CN, trade mark, ex Idemitsu Petrochemical Co.,

[0134] density: 0.907 g/cm³,

[0135] melt index, determined at 190° C. and a load of 2.16 kg: 3.3 g/10min.

[0136] Component (d): propylene homopolymer, PP CJ700, ex MitsuiPetrochemical Industries Inc.,

[0137] crystallization degree: Tm 166° C., ΔHm 82 mJ/mg,

[0138] Component (e): inorganic filler,

[0139] calcium carbonate, RS400, trade mark, ex Sankyo Seihun Co.,

[0140] used in Examples 1 to 5 and Comparison Examples 1 to 10.

[0141] talc, JA13R, ex Asada Seihun Co.,

[0142] used in Examples 6 to 11 and Comparison Examples 11 to 17.

[0143] Component (f): organic peroxide KayahexaAD, trade mark, ex KayakuAkzo Co.

[0144] Component (g): crosslinking aid

[0145] NK ester 3G, trade mark, ex Shin-Nakamura Chemical Co.,

[0146] type: triethylene glycol dimethacrylate

[0147] Component (h): antioxidant

[0148] Irganox B220, trade mark, ex Nippon Ciba-Geigy

Examples 1 to 5 and Comparison Examples 1 to 10

[0149] Each component was used in the amount indicated in Tables 1 and 3in part by weight. First, the whole amounts of components (a), (b), (d),(e) and (h) and a part of component (c), which amount is indicatedbefore symbol “+” in Tables 1 and 3, were charged all together into atwin-screw extruder with an L/D of 62.5 and started to be melt kneadedat a kneading temperature of 180 to 240° C. and a screw rotation speedof 350 rpm. Next, the whole amounts of components (f) and (g) were sidefed and the melt kneading was still continued. Subsequently, theremaining part of component (c), which amount is indicated after symbol“+” in Tables 1 and 3, was side fed, melt kneaded and pelletized. Thepellets obtained were put in a predetermined mold and then pressed inthe conditions of 220° C. and 50 kg/cm² to prepare each sheet for theaforesaid evaluation methods (1) to (8). For the evaluation methods (9),(11), (12) and (13), the pellets thus obtained were injection molded inthe conditions described in evaluation method (9) and subjected to eachtest.

[0150] The results are as shown in Tables 2 and 4. TABLE 1 Component,Example part by weight 1 2 3 4 5 (a) 100 100 100 100 100 (b) 150 150 140140 150 (c-1) 30 + 0 10 + 0 10 + 0 10 + 0 30 + 0 (c-2) 50 + 25 50 + 2550 + 50 50 + 100 50 + 25 (d) 15 15 15 15 15 (e) 60 60 60 60 0 (f)* 0.750.75 0.75 0.75 0.75 (g)* 1.35 1.35 1.35 1.35 1.35 (h)* 0.4 0.4 0.4 0.40.4

[0151] TABLE 2 Example 1 2 3 4 5 Properties of the composition Specificgravity 0.98 0.98 0.99 0.98 0.90 Hardness, 58 65 69 80 75 after HDA 15seconds Tensile strength, 9.5 11.9 13.1 15.1 12.4 MPa 23° C. 60° C. 1.51.8 2.1 3.5 2.0 80° C. 0.5 0.7 1 1.6 0.7 Tensile elongation, % 910 780840 850 1180 Stress at 100% 1.5 2.1 2.2 3.1 2.0 elongation, MPa Tearingstrength, kN/m 27 35 37 42 35 Impact resilience. % 42 41 41 40 55Compression set, % 63 63 66 68 82 Oil resistance Tensil strength 8 10 1215 10 retained, % Elongation retained, % 11 12 13 14 14 Moldability ◯ ◯◯ ◯ ◯ leedout property ◯ ◯ ◯ ◯ ◯ Results of DSC, ° C. Tg₁ 29.4 — — — —Tm₁ 115.5 — — — — Tm₂ — — — — — Tc₁ 86.6 — — — — Tc₂ 102.3 — — — —Gloss, % 37 — — — —

[0152] TABLE 3 Comparative Example Component, part by weight 1 2 3 4 5 67 8 9 10 (a) 100 100 100 100 100 100 100 100 100 100 (b) 150 20 250 140140 140 140 140 150 150 (c-1) 30 + 0 10 + 0 10 + 0 3 + 0 10 + 0 10 + 010 + 0 10 + 0 30 + 0 — (c-2) 50 + 25 50 + 100 50 + 100 0 50 + 300 50 +50 50 + 50 50 + 50 75 + 0 — (c-3) for comparison — — — — — — — — — 105(d) 15 15 15 15 15 0 80 15 15 15 (e) 60 60 60 60 60 60 60 150 60 60 (f)*0 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 (g)* 0 1.35 1.35 1.351.35 1.35 1.35 1.35 1.35 1.35 (h)* 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.40.4

[0153] TABLE 4 Comparison Example 1 2 3 4 5 6 7 8 9 10 Properties of thecomposition Specific gravity 0.98 1 0.94 0.99 0.96 0.99 0.98 1.08 0.980.98 Hardness, 59 93 54 48 91 58 83 80 63 65 after HDA 15 secondsTensile strength, MPa 23° C. 15.5 18.5 9.8 7.2 19.8 4.8 11.9 3.2 7.512.0 60° C. 0.3 — — — 4.8 — 2 — — — 80° C. 0 — — — 2 — 1.1 — — Tensileelongation, % 800 230 450 480 790 80 670 240 650 480 Stress at 100%elongation, MPa 1.3 5.3 1.8 1.2 5.2 — 4.2 2.8 1.5 2.1 Tearing strength,kN/m 30 62 30 — 74 15 51 12 35 27 Impact resilience, % 46 35 38 — 34 4036 25 41 42 Compression set, % 67 83 70 — 72 73 68 80 55 63 Oilresistance Tensile strength retained, % 0 — — — 31 — 18 10 18 10Elongation retained, % 0 — — — 65 — 23 5 15 12 Moldability ◯ X ◯ X ◯ X ◯X ◯ Δ Bleedout property ◯ ◯ X ◯ X ◯ X ◯ ◯ ◯ Results of DSC, ° C. Tg₁28.2 — — — — — — — — — Tm₁ 116.7 — — — — — — — — — Tm₂ 157.4 — — — — — —— — — Tc₁ 87.2 — — — — — — — — — Tc₂ 102.8 — — — — — — — — — Gloss, % —— — — — — — — — 10

[0154] The resin composition in Example 1 was prepared according to theprocess of the present invention, while one in Comparison Example 1 wasprepared in the same conditions as in Example 1, except that components(f) and (g) were not added. It was found that the oil resistance wasvery low in Comparison Example 1. From the results of DSC determination,in Example 1, the melting temperature of polyethylene, Tm₁, decreasedand the melting temperature of polypropylene, Tm₂, disappeared. Thecrystallization temperatures of polyethylene and polypropylene, Tc₁ andTc₂, respectively, decreased slightly. From these data, it is consideredthat some interaction between polyethylene and polypropylene occured,whereby a state near partial compatibility one was obtained. The glasstransition temperature, Tg₁, increased, and become considerably high inExample 1. It is considered that this was due to the considerable phaseseparation of crystal and non-crystal parts of polyethylene, as a resultof the process of the present invention.

[0155] In Examples 2 to 4, the amount of component (c) added was varied.All of the compositions exhibited good characteristic values. It wasfound that the larger the amount was, the better the characteristicvalues were. The composition in Example 5 did not contain component (e).It also exhibited good characteristic values.

[0156] Meanwhile, in Comparison Example 2, the amount of component (b)added was below the range of the present invention. The tensile strengthwas very low and the moldability was poor. In Comparison Example 3, theamount of component (b) added was above the range of the presentinvention. The tensile elongation was very low and bleedout occuredconsiderably. In Comparison Example 4, the amount of component (c) addedwas below the range of the present invention and was introduced all intothe extruder in the former kneading step. The tensile elongation wasvery low and the moldability was poor. In Comparison Example 5, theamount of component (c) added was above the range of the presentinvention. The bleedout property was poor. In Comparison Example 6,component (d) was not blended. The tensile elongation was very low andthe moldability was poor. In Comparison Example 7, the amount ofcomponent (d) added was above the range of the present invention. Thetensile elongation was low and the bleedout property was poor. InComparison Example 8, the amount of component (e) added was above therange of the present invention. The tensile elongation, tearingstrength, impact resilience and oil resistance were poor and themoldability was also poor. In Comparison Example 9, wherein thecomposition was same as in Example 1, all of the components was meltkneaded all together. The tensile strength and tensile elongation werelower than those in Example 1. It was found that the hardness was highand softness decreased. In Comparison Example 10, use was made of anormal polyethylene which had not been polymerized by a single sitecatalyst, in place of component (c) in Example 1. The tensile elongationwas lower, the hardness was higher and the softness decreased, comparedto those in Example 1. It was also found that the gloss decreasedconsiderably and thus the brightness on the surface of the moldedarticle deteriorated extremely. It is considered that this is caused bypoor dispersibility of the resins, compared to Example 1.

Examples 6 to 11

[0157] In Examples 6 to 11, components (a), (c) and (d) and optionally(e) were charged all together into a twin-screw kneader, kneaded at akneading temperature of 180 to 240° C. and a screw rotation speed of 100rpm and pelletized. The pellets obtained were put in a predeterminedmold and pressed in the conditions of 220° C. and 50 kg/cm² to preparesheets for the aforesaid evaluation methods (1) to (6). The results areas shown in Table 5.

Comparison Examples 11 to 12

[0158] The same procedures were repeated as in the aforesaid Examples,except that each of the following polyethylenes which had beenpolymerized without using a single site catalyst was used in place ofcomponent (c).

[0159] Polyethylene for Comparison Example 11,

[0160] V-0398CN, ex Idemitsu Petrochemical Co.,

[0161] type: HDPE (high density polyethylene)

[0162] density 0.907 g/cm³

[0163] melt index, determined at 190° C. and a load of 2.16 kg: 3.3 g/10min.

[0164] Polyethylene for Comparison Example 12,

[0165] 440M, ex Idemitsu Petrochemical Co.,

[0166] type: LLDPE (linear low density polyethylene)

[0167] density: 0.954 g/cm³

[0168] melt index, determined at 190° C. and a load of 216 kg: 10 g/10min

[0169] The results are as shown in Table 5. TABLE 5 Ex. 6 Ex. 7 Ex. 8Ex. 9 Ex. 10 Ex. 11 Comp. Ex. 11 Comp. Ex. 12 Component (a) 100 100 100100 100 100 100 100 Component (c) , c-1 100 100 100 130 70 100 100 100Component (d) 30 45 60 45 45 45 45 45 Component (e) 20 Specific gravity0.89 0.89 0.89 0.89 0.89 0.92 0.9 0.92 Hardness, 70 77 84 86 87 79 9650* after HDA 15 seconds Tensile strength, MPa 28 33 38 32 43 30 24 28Tensile elongation, % 560 570 590 580 600 530 530 230 Stress at 100%elongation, MPa 3.5 4 5 4.5 5.4 3.8 2.8 4.2 Impact resilience, % 60 5855 56 58 54 42 40 Compression set (125° C. × 1 hr), % 44 47 50 61 56 4480 90 Moldability ⊚ ⊚ ⊚ ⊚ ⊚ ⊚ ◯ X Residue after evaporation ofn-heptane, ppm 80 80 80 100 60 70 70 70 Residue after evaporation ofwater, ppm 0 0 0 0.5 0 0 0 0 Residue after evaporation of 10 10 9 2 9 8— — 20% ethenol, ppm Potassium permanganate, ppm 0.3 0.3 0.2 0.8 0.2 0.30.5 1

Comparison Examples 13 to 17

[0170] The same procedures were repeated as in the aforesaid Examples,except that components (a), (c), (d) and (e) were used in an amountexceeding or below the range of the present invention. The results areas shown in Table 6. TABLE 6 Comp. Ex. 13 Comp. Ex. 14 Comp. Ex. 15Comp. Ex. 16 Comp. Ex. 17 Component (a) 100 100 100 100 100 Component(c) , c-1 100 100 3 180 100 Component (d) 3 100 45 45 45 Component (e)120 Specific gravity 0.89 0.89 0.89 0.89 1.05 Hardness, 65 94 90 79 93after HDA 15 seconds Tensile strength, MPa 25 35 46 33 4.5 Tensileelongation, % 630 550 630 600 60 Stress at 100% elongation, MPa 2.5 8.57 4 — Impact resilience, % 55 41 55 58 25 Compression set (125° C. × 1hr), % 95 92 42 90 — Moldability X ◯ ◯ ◯ X Residue after evaporation ofn-heptane, ppm 120 110 80 130 — Residue after evaporation of water, ppm0.6 0.3 0 0.3 — Residue after evaporation of 3 2 5 3 — 20% ethenol, ppmPotassium permanganate, ppm 0.9 0.3 0.2 0.5 —

1. A process for the preparation of a thermoplastic elastomeric resincomposition comprising melt kneading (a) 100 parts by weight of a blockcopolymer consisting of at least two polymeric blocks (A) composedmainly of a vinyl aromatic compound and at least one polymeric block (B)composed mainly of a conjugated diene compound, and/or a hydrogenatedblock copolymer obtained by hydrogenating said block copolymer, (b) 40to 240 parts by weight of a non-aromatic softening agent for rubber, (c)5 to 300 parts by weight of polyethylene or a copolymer composed mainlyof ethylene, and (d) 5 to 60 parts by weight of polypropylene or acopolymer composed mainly of propylene, characterized in that theprocess comprises the following steps: (I) melt kneading the wholeamounts of components (a), (b) and (d) and a part of component (c), and,at the same time or subsequently, melt kneading these with (f) anorganic peroxide, and (II) melt kneading the product obtained from step(I) with the remaining part of component (c), and component (c) is onewhich has been prepared using a single site catalyst.
 2. The process asdescribed in claim 1, wherein a weight ratio of the amount of component(c) used in step (I) and that in step (II) is 90:10 to 10:90.
 3. Theprocess as described in claim 1, wherein component (f) is used in anamount of 0.1 to 1.5 parts by weight per 100 parts by weight of a totalamount of components (a), (b), (c) and (d).
 4. The process as describedin claim 1, wherein 0.1 to 3.5 parts by weight of a crosslinking aid per100 parts by weight of a total amount of components (a), (b), (c) and(d) are used together with component (f) in step (I).
 5. The process asdescribed in claim 1, wherein the whole amount of (e) at most 100 partsby weight of an inorganic filler is melt meaded in the initial stage ofstep (I).
 6. A thermoplastic elastomeric resin composition comprising(a) 100 parts by weight of a block copolymer consisting of at least twopolymeric blocks (A) composed mainly of a vinyl aromatic compound and atleast one polymeric block (B) composed mainly of a conjugated dienecompound, and/or a hydrogenated block copolymer obtained byhydrogenating said block copolymer, (c) 5 to 150 parts by weight ofpolyethylene or a copolymer composed mainly of ethylene, and (d) 5 to 80parts by weight of polypropylene or a copolymer composed mainly ofpropylene, characterized in that component (c) is one which has beenprepared using a single site catalyst.
 7. The thermoplastic elastomericresin composition as described in claim 6, wherein the compositionfurther comprises (b) 40 to 240 parts by weight of a non-aromaticsoftening agent for rubber.
 8. The thermoplastic elastomeric resincomposition as described in claim 6, wherein the composition furthercomprises (e) 0.01 to 100 parts by weight of an inorganic filler.